Aside from having to adjust to a new currency, I sometimes need to deal with a new measure of weight, especially when buying groceries at the wet market.
The tael or loeng2 (両) is one such unit of weight, as seen on this scale. The catty or gan1 (斤) is perhaps the one unit that I hear of the most often when getting vegetable for instance. This is used commonly in small grocery stores (maybe big ones too) and in wet markets alike. A gan1 is worth ~604.8 g and ~1.333 lb, a measure in the same “Western” range of weighing in kg or lbs, which is generally used for consumer-quantities of food.
These are Hong Kong units of measurement, formed under the influence of the British imperial system.